Democrat Baron Hill is dropping out of the Indiana Senate race and will be replaced as the Democratic nominee by former Sen. Evan Bayh, upending the race in a state Republicans expected to hold easily this fall.

Bayh, who is also a former governor of Indiana, still has approximately $9.3 million in a federal campaign account that has sat nearly dormant since he left the Senate in 2010. GOP Sen. Dan Coats won the seat that year but will retire in January.

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Hill, a former House member, was preparing to face GOP Rep. Todd Young in the general election.

Hill’s campaign manager, Brad Howard, told POLITICO on the phone that Hill is leaving the race and Bayh is replacing him, but said afterward he meant to be talking to someone who is not a member of the news media .

Hill’s departure and his replacement by the many-times-elected Bayh dramatically change both the Indiana campaign and, by extension, national Democrats’ quest to retake the Senate majority this fall. Democrats are already directing significant resources into taking a number of GOP-held seats, but Indiana ha d not been one of them . Hill raised less than $1 million in the first 10 months of his campaign, and Young was expected to win the seat easily this fall.

Bayh presents a more formidable obstacle, though his post-Senate legal career is sure to be an opposition-research minefield for him, especially in an election defined by anger at government and career politicians.

In a letter explaining his decision to drop out of the race, Hill indicated he doesn’t think he had what it takes to win. But, without naming names, he said another Democrat might.

“Democrats have a very real chance at winning this Senate seat, especially with a strong nominee who has the money, name identification and resources to win,” Hill wrote. “I intend to stay involved and do everything I can to help elect a Democrat to the U.S. Senate. I hope you will continue to do the same.”

Bayh praised Hill in a statement and said the two had spoken, but gave away little about his plans.

“Baron Hill has always put Indiana first, and has been focused on setting aside party differences to strengthen our state and country. I share this commitment, and agree with him that the stakes have never been higher,” Bayh said.

Republicans immediately seized on Bayh’s work for the lobbying and law firm McGuireWoods on Monday. NRSC Executive Director Ward Baker called Bayh “the definition of a Washington insider” in a statement, and said that Bayh “is a lobbyist who backed the Obama agenda 96 percent of the time as he left the Senate in 2010.”

Young campaign manager Trevor Foughty said that Bayh “left Indiana families to fend for themselves so he could cash-in with insurance companies and influence peddlers as a gold-plated lobbyist.”

“This seat isn't the birthright of a wealthy lobbyist from Washington,” Foughty continued.

But Bayh will likely force national Republicans to spend money on a new battleground state outside the core map of swing states that had been developing for months. As of the last FEC deadline, Bayh already had more federal campaign cash than any battleground Senate candidate except Ohio GOP Sen. Rob Portman.

Senate Leadership Fund spokesman Ian Prior said Monday that the GOP Senate super PAC “ intends to do whatever it takes to help elect Young.

“ K-Street lobbyist and Georgetown resident Evan Bayh’s checkbook is formidable, but he’s going to need every penny of that and more to hide from his own record, ” Prior wrote in an email.

Bayh’s longtime political adviser Dan Parker said in 2015, after Coats announced his retirement, that Bayh would not run for Senate. But his calculation clearly changed in the intervening months, during which time Donald Trump became the Republican presidential nominee and congressional Democrats began planning their down-ballot campaigns around the New York real estate tycoon’s unpopularity.

Bayh, a son of former Sen. Birch Bayh, was elected governor of Indiana in 1988 and served two terms before winning a Senate seat in 1998. But he has been out of politics for the last seven years, which he spent working for McGuireWoods, a step many former lawmakers take upon leaving office. But now that Bayh is running again, it will open him up to criticism that he cashed in on his status as a political insider.

Bayh announced he was leaving the Senate in 2010. In a searing op-ed for T he New York Times title d “Why I’m Leaving the Senate,” he cited Washington’s partisan culture and the role of money in politics as reasons why.

“If fundraising is constantly on members ’ minds, it’s difficult for policy compromise to trump political calculation,” Bayh wrote at the time.

Bayh joined McGuireWoods, where he is a partner, and an investment company after leaving the Senate. He also joined Fox News as a contributor, garnering some criticism from Democrats. Bayh is not a registered lobbyist, but he served as a “strategic adviser to many of the firm ’ s most significant clients, particularly those whose business goals are impacted by the actions of Congress, the executive branch, or by governors and legislators across the country,” according to his official biography on the firm’s website.